Seladonia glacialis (Ebmer, 1979) stat. nov.

Halictus (Seladonia) confusus glacialis Ebmer, 1979: 121. Syntypes ♀ ♂; Spain: Sierra de Guadarrama (AWEC).

Seladonia (Pachyceble) confusa glacialis in Pesenko 2004: 110.

Seladonia (Pachyceble) confusa in Ghisbain et al. 2023: 111.

Notes. Ebmer (1988b) treats the taxa Halictus alpinus Alfken, 1907, Halictus perkinsi Blüthgen, 1926, and Halictus confusus glacialis Ebmer, 1979 as subspecies of the North American Halictus confusus Smith, 1853 (described from Hudson Bay, Canada). However, this situation is unsatisfactory because an examination of the genetic sequences of Central European specimens of “ H. confusus ” in the international genetic database BOLD (https://www.boldsystems. org/) shows that the North American specimens are genetically at least 6% different from the Central European specimens (based on COI). In addition, the American population has several clades and it cannot be ruled out that several species are hidden among them. Therefore, the previous solution of considering both populations east and west of the Atlantic as subspecies of each other is not sensible. The European taxa should therefore be treated as independent species.

Distribution. Mountains of Central Spain and northern Portugal (Ortiz-Sánchez & Pauly 2017).

The second problem concerns the taxon Halictus alpinus Alfken, 1907, as this name should actually be used for the European taxon if treated as one species, because it is the oldest available name. Ebmer (1988b), for European taxa, considers H. confusus alpinus and H. confusus perkinsi. However, a meaningful definition of a subspecies is hardly possible, especially due to the new developments in the genetic analysis of species, and is no longer used in most modern taxonomic works. In the present case, H. confusus alpinus can also be morphologically distinguished from the European “ H. confusus perkinsi ” (see Ebmer 1988b for recognition). Both taxa also differ clearly in their distribution. While “ H. confusus perkinsi sensu Ebmer ” is a species of dry and warm habitats in the plains, H. confusus alpinus, as the name suggests, occurs exclusively in the lower and middle altitudes of the Alps. According to Ebmer (1988b), there are “transitional forms” in warm Alpine valleys in Austria. See also comments of Praz et al. (2023) about the difficulties to separate Halictus confusus alpinus and Halictus confusus perkinsi in Switzerland. But apart from this, the range of both forms is clearly separated.

For these reasons (different morphology and distribution), we consider Seladonia alpina and Seladonia perkinsi as valid species in the genus Seladonia, and unique names are available for both taxa: (i) Seladonia alpina (Alfken, 1907) for the alpine species from Alps and the Pyrenees, and (ii) Seladonia perkinsi (Blüthgen, 1926) for the widespread species outside the Alps and the Pyrenees.

Genetically, S. alpina and S. perkinsi are very close, but they form reciprocally monophyletic groups (Fig. 11). Whilst the genetic distance between the two taxa is small in absolute terms and is equal to 1.64%, but the reciprocally monophyletic nature of the topology as well as the ecological distribution support specific status.

Another taxon from this species group is “ Halictus (Seladonia) confusus glacialis Ebmer 1979 “, described from the Sierra de Guadarrama in Central Spain. Ebmer (1988b) writes [original text in German]: “This geographically isolated subspecies differs distinctly in its external characteristics and was placed with confusus only because of the genital structure of the males. According to the external characteristics it should be classified as a separate species analogous to the characteristics of the other species of the H. tumulorum group”. Based on the barcode, S. glacialis is clearly genetically distinct as it is placed as sister to tumulorum +(alpina +perkinsi), the genetic distance between glacialis and perkinsi + alpina is equal to 6.54% (Fig. 11).

If the name “ confusus ” is no longer appropriate for the European fauna, the cleanest solution is to elevate glacialis Ebmer to species rank, just like the other two former “subspecies”. This solution is nomenclaturally the simplest and does not change anything with its position in relation to other species.